Chances are that if you need to downgrade the firmware, you also need to overwrite the recovery partition in order for it to work. Before you do the downgrade, follow the directions at the bottom of the guide to downgrade the stock 51.1.0 recovery partition.

BTW, I use the AFTV guide, but I also use the "Amazon FireTV Utility App" to automate a lot of the processes, like fully unlocking the bootloader, etc.

I tried again to downgrade and even tried to upgrade using the AFTVNews guide. The result is the same whether upgrading or downgrading. update.zip copies fine Fire TV reboots and stays on white Amazon Logo with yellow light on Fire TV. Probably something I am missing but not sure what. I have rooted and installed custom recovery, unlocked bootloader on other Fire TV so I have a pretty good idea what I'm doing, just not sure what I'm missing on the downgrade

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